... the Dardanelles is about twelve leagues long, three miles wide at its entrance, and about three-quarters of a mile at its narrowest point.
Its principal defences are the outer and inner castles of Europe and Asia, and the castles of Sestos and Abydos.
Constantinople stands about one hundred miles from its entrance into the Sea of Marmora, and at nearly the opposite extremity of this sea. The defenc...